1. Field of the Invention
2. Description of the Related Art
The invention relates to a screw with a shank provided at least partly with a thread, a boring and/or penetrating point and a head equipped with a tool drive for fastening wooden laths to a roof or wall substructure comprising wood among other alternatives.
Heretofore laths, especially roof laths, have normally been fastened by nails, even though tensile loading of nails in shank direction should be zero or only slight. Predrilled holes are necessary to ensure that the nailing process does not cause splitting, especially in the case of larger nails.
Precisely in the fastening of laths on which the actual roof covering or wall siding will ultimately be fastened, it is the roof or wall structure that is usually the weak point, because tensile forces developed during suction effect cannot be transmitted.
The use of screws has never been considered, because of the risk of splitting of the relatively narrow laths by the screw head as the screws are being tightened.
The object of the invention is to provide a screw of the type cited in the introduction, which screw is particularly suitable for use in fastening wooden laths to a roof or wall substructure.